1. Field of the Invention
The present invention relates to an articulating or folding mast that may be transported from one well drilling site to another. In particular, the present invention relates to a folding mast wherein sections of the mast may be moved from an open, in-use position to a folded position for storage and transportation and then moved from the folded position to an open position for use.
2. Prior Art
In oil and gas operations, well drilling rigs are utilized to drill for reserves. Many times drilling does not result in a productive well and it has been estimated that over two million boreholes have been dug world wide.
A mast or derrick of a drilling rig supports a vertically moving block and tackle in order to raise and lower drill pipes. Masts or derricks are well known for use in oil and gas and other drilling operations. A mast often extends up to 200 feet and is often composed of structural steel framework which supports a crown assembly. The crown assembly is an arrangement of sheaves at the top of the mast or derrick directly above the well bore.
Various drilling structure arrangements are known although one arrangement includes a pair of sides with a back face joining the sides and an open front face. A mast is typically braced on three sides with an open front face to receive pipe sections.
As drilling is conducted, the drill bit becomes dull and the whole drill string has to be taken out of the hole and the bit replaced. In addition, casing, consisting of thick-walled pipes are screwed together and lowered into the well.
From time to time, once a drilling project has been completed, it is required to move the drilling rig from one location to another location. In one known arrangement, the entire drilling rig is disassembled piece by piece, then transported to the next location, and then reassembled.
As a technological advance on the complete disassembly and reassembly of the mast, a folding gin pole arrangement was developed. The entire mast could be moved from vertical to a horizontal position by a wire line extending from the crown to a gin pole at the base. Once on the ground, the mast could be disassembled. Normally, the mast sections are transported by trailer. Disassembly of the sections is normally required due to roadway limits as to height and width.
The mast may be divided into sections and the sections of the mast moved to a new location. Accordingly, it would be desirable to be able to fit the various mast sections onto trailers.
Additionally, it would be advantageous for the mast sections to be able to meet roadway requirements for size of load. For example, certain highway regulations limit the width of the load to twelve feet. Accordingly, it would be advantageous to provide a mast wherein sections may be folded to a width acceptable for roadway requirements.
It would also be advantageous to provide a mast having sections that may be moved between an open, in-use position and a folded position for storage and transportation.
It would also be advantageous to provide a mast having sections that may be locked in either an open, in-use position or a folded position.
It would also be advantageous to provide an articulating mast wherein the required disassembly and subsequent re-assembly is reduced.
The present invention provides an articulating mast which will be used in connection with well drilling. In position for use, the mast will be aligned vertically to the ground over a well bore.
In a preferred embodiment, the mast may include a sub base, a bottom section, a lower intermediate section, an upper intermediate section, a top section and a crown assembly section. Each of the adjoining sections may be pinned together to form the mast. In a preferred embodiment, the mast will include a pair of opposed sides and it will also include a back face connecting the sides together. The front face will generally be open but may include a tubing support assembly and a racking platform assembly. The open front face permits the entry and removal of tubing sections in connection with the drilling operation.
In a preferred embodiment, the mast will include four legs which will be pyramidal in structure with the widest cross section at the sub base and thereafter tapering towards the more narrow portion at the crown assembly.
The back face includes a plurality of pairs of back face cross supports. Each pair of back face cross supports spans the back face and connects with the opposed sides and, in particular, connects to the legs of the sides.
Additionally, the back face includes a plurality of angled braces which extend between the cross supports and the legs of the sides.
Each pair of cross supports is joined together to span the back face. Each individual cross support has a first and a second opposed end. Each of the second ends are pivotally connected to each other through a bushing. The bushing may be a misaligning bushing having a ball inside of a race.
Each first end of the cross support is pivotally connected to one of the legs. Each first end will be permitted to rotate through an axis about a hinge pin. Each first end terminates in an extending ear having an aperture therethrough. As the first end rotates, the extending ear moves between a storage position and an open position. The aperture will align with an opening in the open position and will align with an opening in the storage position.
Each of the angles braces will be pivotally connected with a leg. Each angled brace will articulate with respect to the leg and rotate about a pivot.
In order to unfold the mast section and move the section to the open position, a lifting beam and a spreader bar or bars may be utilized. The spreader bar will be attached between the cross supports near the bushing. The spreader bar in turn will be connected to the lifting beam. The lifting beam may be attached by an eye or otherwise to a wire line and a lifting mechanism such as a crane or tractor. The lifting beam and spreader bars may be detached from the mast section once the section is in the fully opened position.